Stress and the Risk of a Heart Attack

Thursday, June 19, 2014 | 1:26 am

Mrs. Lopez came to the ER complaining of chest pain one hour after her brother who was suffering from metastatic cancer passed away. Her husband initially thought her chest pain as because of her grief but when it did not go away he called 911. Mrs. Lopez’s evaluation in the ER revealed she had a heart attack.

We know that stress is linked to heart attacks but the exact reason as to how stress causes a heart attack is unknown but new research is shedding some light on the process. A study published in mBio suggests that stress hormones can break up bacteria growing on atherosclerotic plaques in arteries, releasing the plaques and causing strokes or heart attacks.

Plaques form a surface on which bacteria can attach and grow in masses called biofilms. Bacteriologist David Davies of Binghamton University in New York analyzed arteries from 15 patients with cardiovascular disease. Using fluorescent tags that mark bacterial DNA, they discovered at least 10 species of bacteria clustered tightly around the plaques, including the biofilm-forming Pseudomonas aeruginosa.

If these biofilms are tightly attached to plaques, they may have an effect on cardiovascular disease, Davies says. Plaques in blood vessels are normally stable, but if they break up and enter the bloodstream, they can trigger blood clots that lead to heart attacks or strokes.

To test their hypothesis, the researchers grew P. aeruginosa in artificial arteries made of silicone tubing and waited for the bacteria to form biofilms. They then flooded the tubes with the stress hormone noradrenaline, which caused the biofilms to break up.

Stress hormones in the blood trigger the body’s cells to release iron into the bloodstream. The iron causes bacteria such as P. aeruginosa to produce enzymes that sever the polymer bonds that hold the bacteria together in the biofilm matrix and attach the bacteria to the plaque. The plaque is broken up as collateral damage, Davies says. Although he says that much more research in animals and humans is needed, the work “introduces a completely unexpected potential culprit” in the mystery of how plaques trigger heart attacks, he adds.

The next step is to study if the same process occurs in an animal model and Davies says that he plans to model the process in mice. He and his team are also planning to determine whether the arteries of healthy people contain biofilm-forming bacteria.

The most important thing to remember is reducing stress levels can potentially reduce your risk of a heart attack and the American Heart Association does recommend stress reduction as part of a healthy preventative lifestyle plan to prevent a heart attack or stroke.

Dr. Joshua A. Jacobi, MD, Cardiovascular Disease, Healthy Living Medical, 301 S. Fair Oaks Ave. Ste 404, Pasadena, (626) 716-9206 or visit www.thehealthylivingmedical.com.

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